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F. W. ROBINSON.

DROP STITCH MECHANISM FOR. KNITTING MACHINES.

APPLICATION-FILED FEB. 20. 1919.

Patented May 11, 1920.

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FRANK W. ROBINSON, 0F READING, PENNSYLVANIA, ASSIGNOR T0 T12-IIE.NOLDIEV 8c HORST CO., OF READING, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

DROP-STITCH IVIECHANISM FOR KNI'ITING-IVIACHINES.

Specification of Letters Patent.

Patented May 11, 1920.

Application filed February 20, 1919. Serial No. 278,188.

To all whom 'i1/may concern:

Be it known that I, FRANK W. ROBINSON, a citizen of the United States, residing at Reading. in the county of Berks and State of Pennsylvania, have invented certain new and usei'ul Improvements in Drop-Stitch Mechani sm for Knitting-Machines, ot which the following is a specification.

My invention relates particularly to circular knitting machines adapted to produce stockings having drop-stitch stripes upon the entire leg and upon the upper portion only of the toot; and it consists in the improyed needleoperating` mechanism hereinaiter fully described in connection with the accompanying drawing and the novel features of which are clearly defined in the claims.

Figure 1 is a plan view showing a cam ring having my improvements applied thereto.

Fig. 2 is an elevation of a known type of machine indicating operating means for the movable needle-engaging cams employed.

Fig. 3 is an interior diagrammatic view of the developed cam ring.

Fig. fl indicates the three diEerent lengths of butts provided upon the otherwise similar needles employed; and Fig. 5 indicates the relative arrangement of these differently butted needles.

Fig. 6 indicates a known continuous stocking-fabric product of my improved machine.

The relative rarrangement of the long-butt needles 10, medium-butt needles 11, and short-butt needles 12, in the rotary needle cylinder 1` as indicated in Fig. 5, corresponds with that shown in my prior Patent No. 1,262,568, issued April ninth, 1918; as does also the general knitting action of the needles in producing a uniform drop-stitch effect upon the circularly knitted leg portions of the fabric indicated in Fig. 6, in connection with a solid formation of the reciprocatively knitted heel and toe portions and oi the bottom only vof the circularly knitted foot portion thereof.v My present invention consists in improved needleoperating cam mechanism whereby the actions of the medium-butt drop-stitch needles are specially controlled to avoid any operation thereof during circular knitting, and to secure a tucking action preliminary to the `lrniting of the heel, as hereinafter fully setJ iii.

This improved cam mechanism is illustrated in Fig. 1, and described particularly in connection with diagrammatic view Fig. 8, where dotted lines a and c indicate courses of the long-butt needles 10, mediumbutt needles 11, and short-butt needles 12, respectively. As the front half of the stocking is knitted throughout upon the long-butt needles 10, the desired drop-stitch stripes are produced by merely removing corresponding long-butt needles from the cylinder; but the medium-butt drop-stitch needles 11, which must be out of action during the circular knitting of the leg portion of the stocking, are thrown into knitting action for circular knitting of the foot and reciprocative knitting of the heel and toe, and are also specially operated preliminary to starting the knitting of the heel so as to tuck or gather a plurality of yarn loops. The purpose of this tucking action is to avoid defective knitting which is otherwise liable to occur through failure of the thrown-in needles 11 to pick up the yarn with regularity, a diiculty which is overcome in my prior patent referred to by providing specially long latches .upon certain of the needles 11 but which is diiierently overcome by the present improved needle operating cams.

Fig. 3 shows the usual top center cam 15, right and left stitch cams 17 and 18, and needle rest 19 forming the normal upper run-way for the needles. Below this needle rest I provide a parallel run-way 2O in which the butts of the lowered drop-stitch needles 11 are idly held during the circular knitting of the striped leg; said upper and lower runways however being connected by reversely inclined branches 22 and 23, serving respectively as lowering and raising run-ways for the needles 11. The upper run-way is also provided with a dipped or V-shaped siding 2%25, into which these same needles 11 may be momentarily diverted from the upper run-way to produce the tucking effect referred to. y

The lowering of drop-stitch needles 11 into the lower run-way is effected when desired, by throwing a movable selecting cam into the upper run-way at the point of liunction with the lowering branch 22. This cam, as shown, has reversely inclined face portions 30p- 31: forming an inverted V- shape; the' 'face portion 30 being set back so as to permit the passing of the shortbutt and medium-butt needles, but engaging the long-butt needles to divert them upward; while the face portion 31 permits the passing of the short-butt needles only and engages the 1ne ;liuinbutt needles so as to divert them downward through the low-A ering branch 22 to the lowei run-way LZll. To provide tor temporarily diverting the needles 11 from their normal path into the dipped siding 24-25, for tucking action, l employ an independently movable tuclring cam having similar reversely inclined lace portions adapted to selectively lower said needles under the lixed stitch cani 1T so as to avoid the latch-clearing movement, while returning them for the takin-g on ot a new or additional loop. To provide for returning the needles il from the 'lower run-way 2O in which they are subjected to no raising or lowering movement, to the upper run-way and normal l-nitting action, l employ 'a switch cam slt) movable into said lower run-wav at the junction olf the raising branch 20, this 'am being preferably connected with the tucking ram 355-36 vfor joint operation, as indicated, inasmuch as the retaining of the switch cam in operative position while the tucking cam is operated, produces no effect.

As indicated in Figs. 1 and 2, the required movements ot the selecting cam 30-31, and combined tucking cam 35-36 and switch cam at), are automaticall)7 eifected at required times by the usual pattern-controlled cam drum 1:5 on. cam shaft 516;I the spring-turned vertical operating shaft 4:7 being rocked by contact of its rollered arm 48 with proper projections and recesses on thc cam drum tace, and the spring-retracted shank portions 50 and 5l of the respective cam devices being selectively operated by engagement ot' a shaft arm 52 with an intermedately pivoted lever 53. In Fig. 'l this lever is in normal inidway position and both the spring-retracted cam devices are withdrawn; but an inward movement of the shaft arm I jn'esses selecting `cam 30-31 into axztion, while an outward movement thc-.root permits a stronger spring to over-nome the retracting spring of combined cam lwice BFSG, flf) and so set the latter into accion.

Duringthe circular knitting el the uniormly striped leg portions indicated in Fig.

"G, lthe medium-butt needles ll are held to the lower run-way 2O without being sub- ,jectedwto any raising or lowering action; but 'ust before the heel is reached, the switc ing cam Ll0 (in connection with t cking cam 3536) is thrown in to raise them through the connecting branch 23 to the upper run-way; which run they :tollow with the other needles, excepting that they are diverted in each course into the dipped siding Ql-Q by the tucking cam 35-36 until the latter is withdrawn. This withdrawal occurs aiter the knitting oit-several tucking courses during which the needles 11 take on several loops without being raised to latchclearing height; and knitting then proceeds as usual, on the medium-butt needles 11 and short-butt needles l2 only to form the heel, second, on all the needles to term the circular toot, and third, on the mediumbutt needles l1 and short-butt needles l2 again to `forni the toe. vAitor the knitting et the toe, a Yfew connecting courses are knitted on all the needles betere resuming the knitting of the next leg oli the continuous liabric indicated .in Fig. G; the starting ot such leg knitting being effected by merely throwing in the dividing cam Btl-3lY to lower the medium-butt needles 1l. into their lower run-way 20 as at the beginning of the described operation.

This lowering et the medium-butt needles to idle position in lower run-way itl, in the knitting or a continuous fabric :lier ladies7 stockings such as is indicated in Fig. (5, takes oil' the yarn loop on such needles by simply tearing the yarn, which is unobjectionable as the continuous fabric is parted by cut- .ing just beyond the toe. The usual dividing cams shown at 60, Gl, need not be employed in connection with the preferred special dividing cams 30-3l and S35-36, but may be employed .in place olI the portions 30 and B5 ot said cams for temporarily raising the long-butt needles 10, which are relowered by a fixed cam (32. The specilic mechanism set forth may be readily modilied without departing from the invention as delined in the claims.

That I claim is :w

l. In a knitting machine comprising an approximate half-circle of needles having long butts and an approximate half-circle some of which have short butts and others medium butts; a needle-operating mechanism comprising parallel upper and lower run-ways for the needles connected by separate lowering and raising branches and said upper run-way having also a dipped siding, a selecting cam movable into said upper runway and loperative upon said long-butt and medium-butt needles to lower the latter only into said lower run-way, a switch cam movable into said lower run-way to re-raisesaid lowered needles, and a tucking cam movable into said upper run-way and operative upon said long-butt and medium-butt needles to 'deflect the latter only into said dipped sidlower run-ways ior the needles connected by separate lowering and raising branches and said upper run-way having also a dipped siding, a selecting cam movable into said upper run-way and operative upon said long-butt and medium-butt needles to lower the latter only into said lower run-way, and switch and tucking cams simultaneously movable into said lower and upper run-ways respectively and jointly operative upon said lowered medium-butt needles to traverso them in said dipped siding.

3. In a knitting machine comprising an approximate halt-circle of needles having long butts and an approximate half-circle some oij which have short butts and others medium butts; a needle-operating mechanism comprising selecting-cam faces movable into the normal runway of the needles and operative upon said long-butt and medium-butt needles to lower the latter only, and a continuous lower run-way for said lowered needles connected with the normal race-way by lowering and raising branches and having a switch cam movable tliereinto at the junction of said return branch.

4. In a knitting machine comprising an approximate halt-circle of needles having long butts and an approximate half-circle some oil which have short butts and others medium butts; a needle-operating mechanism comprising an inverted V-shaped selecting cam movable into the normal runway of the needles and having one member set back to engage and raise the long-butt needles only and the other member set back to engage and lower the medium-butt needles only.

5. In a knitting machine comprising an approximate half-circle of needles having long butts and an approximate half-circle some of which have short butts and others medium butts; a needle-operating mechanism comprising two inverted V-shaped cams separately movable into the normal run-way of the needles at different points thereof, one member of each of said cams being set back so as to engage and raise the long-butt needles only and the other member beine set back so as to engage and lower the medium-butt needles only.

6. In a knitting machine comprising an approximate half-circle of needles having long butts and an approximate half-circle some of which have short butts and others medium butts; a needle-operating mechanism comprising connected upper and lower run-Ways Jfor the needles the upper one of which has a dipped siding, and a tucking cam and switch cam jointly movable into junction points of said upper and lower run-ways respectively.

In testimony whereof I ailix my signature.

FRANK W. ROBINSON. 

